Severe hemodilutional anemia increases cerebral tissue injury following acute neurotrauma

Anemia may worsen neurological outcomes following traumatic brain injury (TBI) by undefined mechanisms. We hypothesized that hemodilutional anemia accentuates hypoxic cerebral injury following TBI. Anesthetized rats underwent unilateral TBI or sham injury (n ≥ 7). Target hemoglobin concentrations between 50 and 70 g/l were achieved by exchanging 40–50% of the blood volume (1:1) with pentastarch. The effect of TBI, anemia, and TBI-anemia was assessed by measuring brain tissue oxygen tension (PbrO2), regional cerebral blood flow (rCBF), jugular venous oxygen saturation (SjvO2), cerebral contusion area, and nuclear staining for programmed cell death. Baseline postinjury PbrO2 values in the TBI and TBI-anemia groups (9.3 ± 1.3 and 11.3 ± 4.1 Torr, respectively) were lower than the uninjured controls (18.2 ± 5.2 Torr, P < 0.05 for both). Hemodilution caused a further reduction in PbrO2 in the TBI-anemia group relative to the TBI group without anemia (7.8 ± 2.7 vs. 14.8 ± 3.9 Torr, P < 0.05). The rCBF remained ...